JP6719054B2 - Electrochemical hydrogen pump - Google Patents

Description

The present invention relates to an electrochemical hydrogen pump. In particular, it relates to an electrochemical hydrogen pump that compresses hydrogen.

Household fuel cells that use hydrogen as fuel are becoming more popular as their development progresses. Furthermore, in recent years, mass production and commercialization of fuel cell vehicles that use hydrogen as a fuel, similar to household fuel cells, have begun. However, unlike household fuel cells that can use existing city gas and existing commercial power, hydrogen infrastructure is inevitable for fuel cell vehicles.

Therefore, in order for fuel cell vehicles to expand and spread in the future, it is necessary to expand hydrogen stations as hydrogen infrastructure. However, current hydrogen stations require large-scale facilities and sites, and thus enormous costs. This is a major issue to be solved for the spread of fuel cell vehicles.

Therefore, as an alternative to a large hydrogen station, the development of a compact, inexpensive, small-sized household hydrogen filling device is desired. The most important thing in the development of this compact hydrogen filling device is the development of a compressor that compresses hydrogen, and what is currently attracting attention is an electrochemical hydrogen pump that can electrochemically boost hydrogen.

Electrochemical hydrogen pumps have many advantages compared to conventional mechanical hydrogen compressors, such as compactness, high efficiency, no maintenance required because there is no mechanical operating part, and almost no noise. Is coveted.

At present, the method envisioned for small hydrogen filling devices uses an electrochemical hydrogen pump to generate hydrogen generated by the fuel reformer of a home fuel cell when operation as a fuel cell is stopped. It is a method of electrochemically compressing hydrogen. With such an electrochemical hydrogen pump, in addition to the above-mentioned merits, the concentration of hydrogen generated by using the fuel reformer of at most 75% can be improved to almost 100% of hydrogen, and the fuel cell vehicle can be used. In principle, it is possible to raise the pressure to an extremely high pressure at which filling is possible.

In addition, the structure is almost the same as the power generation stack in the home fuel cell. The major difference from the fuel cell power generation stack is that the pressure of the cathode electrode must be higher than the ultrahigh pressure that can fill the fuel cell vehicle with hydrogen, compared to the anode electrode that supplies low-pressure hydrogen. A special structure is required for the support structure of the membrane.

FIG. 1 shows the structure of a conventional fuel cell power generation stack 1. In FIG. 1, both sides of the electrolyte membrane 2 on which the anode electrode layer 3 and the cathode electrode layer 4 are formed are sandwiched between the anode diffusion layer 5 and the cathode diffusion layer 6, and the outside thereof is sandwiched between the anode separator 7 and the cathode separator 8, The outside is sandwiched between the anode insulating plate 11 and the cathode insulating plate 12, and then fastened with bolts 13 and nuts 14.

Further, an anode seal 9 and a cathode seal 10 are attached around the anode diffusion layer 5 and the cathode diffusion layer 6 so that gas does not leak to the outside. When the fuel cell power generation stack 1 is used as a hydrogen pump, the anode inlet 15 is used for supplying low-pressure hydrogen, the anode outlet 16 is used for recovering excess low-pressure hydrogen, and the cathode inlet 17 is for high pressure. It is used to take out hydrogen, and the cathode outlet 18 is not used, so it is sealed. In this state, the low pressure hydrogen is supplied from the anode inlet 15 by connecting the respective piping ports, and the low voltage hydrogen is flown through the anode flow path 7a, and the voltage is applied between the anode separator 7 and the cathode separator 8 by the voltage applying unit 19. When applied, hydrogen dissociates into protons and electrons in the anode electrode layer 3 according to Formula 1.

Anode: _{H 2} (low ^{pressure) → 2H + + 2e - ···} ( Equation 1)
The protons dissociated in the anode electrode layer 3 move along with the water molecules in the electrolyte membrane 2, and the electrons pass from the anode diffusion layer 5 to the anode separator 7 and the voltage separator 19 to the cathode separator 8 and the cathode diffusion layer 6. Further, it moves to the cathode electrode layer 4. Further, on the cathode electrode side, a reduction reaction is performed by the protons moving in the electrolyte membrane 2 and the electrons transmitted from the cathode diffusion layer 6, and hydrogen is generated. At this time, when the cathode inlet 17 is closed, the hydrogen gas pressure in the cathode flow channel 8b rises and becomes high-pressure hydrogen gas.
Cathode electrode: 2H ⁺ +2e ⁻ →H ₂ (high pressure) (Equation 2)
Here, the relationship between the pressure P1 of hydrogen on the anode side, the pressure P2 of hydrogen on the cathode side, and the voltage E is expressed by Equation 3 below.

E=(RT/2F)ln(P2/P1)+ir... (Formula 3)
In Equation 1, the gas constant (8.3145 J/K·mol) is R, the cell temperature K is T, the Faraday constant (96485 C/mol) is F, the cathode side pressure is P2, the anode side pressure is P1, and the current density is (A/cm ² ) is indicated by i, and cell resistance (Ω·cm ² ) is indicated by r.

As is clear from the equation 3, it is understood that the pressure P2 of hydrogen on the cathode side rises when the voltage is raised.

However, the anode-side skimmer 20 and the cathode-side skimmer 21 for assembly are always required between the anode diffusion layer 5 and the anode seal 9 and between the cathode diffusion layer 6 and the cathode seal 10.

That is, the disk-shaped anode diffusion layer 5 having a diameter φd shown in the perspective view of FIG. 2A is placed in the hole (opening) of the ring-shaped anode seal 9 having the hole (opening) of the inner diameter φD shown in the perspective view of FIG. 2B. In order to be incorporated into, the inner diameter φD needs to be larger than the diameter φd. As a result, after the assembly is completed, the anode-side skimmer 20 having the width δ in FIG. 3 is generated. The width δ of the anode-side skimmer 20 is approximately half the difference between the diameter φd and the inner diameter φD. For example, when the size of the anode diffusion layer 5 is 100 mm in diameter, it is usual to design the reference dimensions of the diameter φd and the inner diameter φD so that the width δ of the anode-side skimmer 20 is about 0.1 mm.

This is because if the difference between the diameter φd and the inner diameter φD is designed too small, the size relationship between the diameter d and the inner diameter D is reversed due to the dimensional variation in manufacturing the anode diffusion layer 5 and the anode seal 9, and the anode diffusion layer 5 is sealed with the anode seal. This is because it may not be possible to assemble it in the hole 9 (opening). Further, it is conceivable that the anode diffusion layer 5 and the anode seal 9 are dimensionally inspected after they are manufactured, and only the acceptable products are used. However, in this case, the yield of the anode diffusion layer 5 and the anode seal 9 is lowered, and the cost is increased. There is a problem that becomes. Therefore, the anode-side skimmer 20 having a width of about 0.1 mm is required between the anode diffusion layer 5 and the anode seal 9.

The same applies to the case of the cathode diffusion layer 6 and the cathode seal 10.

When the fuel cell power generation stack 1 having the anode-side skimmer 20 and the cathode-side skimmer 21 is used as a hydrogen pump to boost the pressure of hydrogen, the cathode-side skimmer 21 acts on the cathode-side skimmer 21 as the pressure on the high-pressure side increases. Due to the pressure of hydrogen, the electrolyte membrane 2 is pushed from the high pressure side (cathode side) to the low pressure side (anode side). That is, the electrolyte membrane 2 is deformed so as to hang down from the high-pressure side cathode-side skimmer 21 to the low-pressure side anode-side skimmer 20. If this deformation becomes severe, the electrolyte membrane 2 will be cracked and will eventually be damaged.

Therefore, it is reported that the pressure of hydrogen that can be boosted by using the power generation stack 1 of a general fuel cell as a hydrogen pump is not so high, and is insufficient for filling a fuel cell vehicle with hydrogen. Therefore, a structure has been proposed in which a power generation stack of a general fuel cell is used as a hydrogen pump and the electrolyte membrane is supported so that the electrolyte membrane is not damaged even if there is a pressure difference between the high pressure side and the low pressure side ( Patent Document 1).

FIG. 4 shows a schematic cross-sectional view of the electrochemical hydrogen pump 22 described in Patent Document 1. According to Patent Document 1, the rigid body in the low-pressure region, that is, the anode diffusion layer 5 is wider than the region in which the high pressure is applied, that is, the inside of the cathode seal 10. That is, the anode-side skimmer 20 and the cathode-side skimmer 21 are not at the same position.

Therefore, even if a high pressure is applied to the electrolyte membrane 2, the pressure can be received by the highly rigid anode diffusion layer 5 on the low pressure side. Therefore, the electrolyte membrane 2 is not subjected to the bending force and the shearing force that cause the damage. Therefore, it is said that the electrolyte membrane 2 can be safely supported even if there is a pressure difference.

International Publication No. 2015/020065

However, in the above structure, only the portion of the cathode electrode layer 4 is effectively used for compressing hydrogen, and the portion of the anode diffusion layer 5 wider than the cathode diffusion layer 6 is expensive Ti. This is a useless part that cannot be effectively used while using the metal sintered body of 2 as a diffusion layer.

Therefore, it is a problem to be solved in order to reduce the manufacturing cost of the hydrogen pump.

Further, it has been found that in the above-mentioned configuration, a performance problem occurs due to the cathode side skimmer 21 on the high pressure side and the anode side skimmer 20 on the low voltage side. That is, during operation as a hydrogen pump, there is a problem that a part of the high-pressure hydrogen diffuses back from the high-pressure side cathode-side skimmer 21 into the low-pressure side anode-side skimmer 20, and the pressure of hydrogen that has been boosted is reduced by the reverse diffusion. is there. That is, the efficiency of the hydrogen pump is reduced.

Therefore, the object of the present application is to make the width of the anode diffusion layer and the width of the cathode diffusion layer substantially the same so as not to hinder cost control, and prevent damage to the electrolyte membrane due to differential pressure without performance degradation. It is to provide an electrochemical hydrogen pump.

In order to solve the above problems, an anode electrode and an anode diffusion layer are located on one surface,
An electrolyte membrane having a cathode electrode and an cathode diffusion layer on the other surface, an anode seal having an opening surrounding the anode diffusion layer, a cathode seal having an opening surrounding the cathode diffusion layer, and an outside of the anode seal. An anode separator located on the outer side of the cathode seal, and a cathode separator located on the outer side of the cathode seal, and outer surfaces of the anode diffusion layer and the cathode diffusion layer are first inclined surfaces. The curved surface is a second inclined surface, and the first inclined surface and the second inclined surface form a mating surface, and the mating surface is an electrical surface that is inclined with respect to the cathode electrode layer and the anode electrode. A chemical hydrogen pump is used.

According to the present invention, since the anode-side skimmer 20 between the anode diffusion layer 5 and the anode seal 9 and the cathode-side skimmer 21 between the cathode diffusion layer 6 and the cathode seal 10 do not exist, the electrolyte membrane 2 is exposed to gas. There is no. Therefore, performance degradation due to hydrogen concentration diffusion from the high pressure side to the low pressure side is suppressed.

Schematic cross-sectional view of a conventional general structure of a power generation stack of a fuel cell 3D perspective view of the anode diffusion layer in Patent Document 2 A perspective view of the anode seal in Patent Document 2 A three-dimensional perspective view of a combination of an anode diffusion layer and an anode seal in Patent Document 2 Schematic cross-sectional view of the electrochemical hydrogen pump in Patent Document 1 Schematic cross-sectional view of the electrochemical hydrogen pump in the first embodiment A cutaway perspective view of the anode diffusion layer in the first embodiment. A cutaway perspective view of the anode seal in Embodiment 1. Breakdown perspective view of the cathode diffusion layer in the first embodiment Fracture perspective view of the cathode seal in the first embodiment Schematic cross-sectional view of the electrochemical hydrogen pump according to Embodiment 1 in a state before compression Schematic cross-sectional view of the electrochemical hydrogen pump evaluation device The figure which shows the result of having evaluated the electrochemical-type hydrogen pump in patent document 2, and the electrochemical-type hydrogen pump in Embodiments 1-3 by the evaluation apparatus of the electrochemical-type hydrogen pump of FIG. A schematic cross-sectional view of an electrochemical hydrogen pump according to a second embodiment of the present invention. A schematic cross-sectional view of an electrochemical hydrogen pump according to a third embodiment of the present invention in a state before being fastened. A schematic cross-sectional view of an electrochemical hydrogen pump according to a fourth embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings.
(Embodiment 1)
FIG. 5 is a schematic sectional view of the electrochemical hydrogen pump 23 according to the first embodiment.
<Overall Configuration> In the electrochemical hydrogen pump 23 according to the first embodiment, the electrolyte membrane 2 having the anode electrode layer 3 and the cathode electrode layer 4 formed on both sides is used as an anode diffusion layer 5, a cathode diffusion layer 6, an anode separator 7, and It is sandwiched between the cathode separators 8. Further, after sandwiching them with the anode insulating plate 11 and the cathode insulating plate 12, they are fastened with bolts 13 and nuts 14. Further, an anode seal 9 and a cathode seal 10 are attached around the anode diffusion layer 5 and the cathode diffusion layer 6 so that gas does not leak to the outside.

The electrolyte membrane 2 is a cation permeable membrane, and for example, Nafion (registered trademark, manufactured by DuPont), Aciplex (trade name, manufactured by Asahi Kasei Corporation), or the like can be used. For example, the anode side surface of the electrolyte membrane 2 is provided with an anode electrode layer 3 containing a RuIrFeOx catalyst, and the cathode side surface is provided with a cathode electrode layer 4 containing a platinum catalyst, for example.

Further, the anode diffusion layer 5 needs to be able to withstand the pressing of the electrolyte membrane 2 by the high-pressure hydrogen in the cathode channel 8b in the cathode separator 8. As the cathode diffusion layer 6, for example, a conductive porous body such as a titanium fiber sintered body or a titanium powder sintered body whose surface is plated with platinum can be used.

The cathode diffusion layer 6 may be, for example, highly elastic graphitized carbon fiber (carbon fiber treated at a high temperature of 2000° C. or higher for graphitization), or platinum plating on the surface of a titanium powder sintered body. It is possible to use a paper-shaped porous body or the like that has been subjected to.

Further, as the anode seal 9 and the cathode seal 10, those produced by compression molding of fluorine rubber can be used. The anode separator 7 and the cathode separator 8 can be formed by cutting a SUS316L plate material to form a cathode flow path 8b, an anode flow path, and the like, respectively.

A broken perspective view of the anode diffusion layer 5 and the anode seal 9 is shown in FIGS. 6A and 6B.

As shown in FIGS. 6A and 6B, the outer side surface of the anode diffusion layer 5 is the first inclined surface α1. The inner surface of the annular anode seal 9 is composed of two curved surfaces, and the upper side of the paper is the second inclined surface β1 and the lower side of the paper is the third inclined surface γ1.

7A and 7B are cutaway perspective views of the cathode diffusion layer 6 and the cathode seal 10.

Similarly, as shown in FIGS. 7A and 7B, the outer surface of the cathode diffusion layer 6 is the first inclined surface α2. The inner side surface of the annular cathode seal 10 is composed of two curved surfaces, and the lower side of the paper surface is the second inclined surface β2 and the upper side of the paper surface is the third inclined surface γ2.

In addition, it is preferable that the outer side surface of the anode diffusion layer 5 and the inner side surface of the anode seal 9 be inclined. That is, it is preferable that these mating surfaces S1 are not perpendicular to the plane of the surface of the electrolyte membrane 2 (electrode layer) but are inclined.

Similarly, it is preferable to incline the outer surface of the cathode diffusion layer 6 and the inner surface of the cathode seal 10. That is, it is preferable that these mating surfaces S2 are not perpendicular to the plane of the surface of the electrolyte membrane 2 (electrode layer) but are inclined.
This eliminates the anode-side skimmer 20 and the cathode-side skimmer 21 shown in FIG.

The angle ε between the mating surfaces S1 and S2 and the plane of the cathode electrode layer 4 and the plane of the anode electrode layer 3 is preferably smaller than 90 degrees.

The range of the angle ε is preferably 45°±30°. It is preferably 45°±20°.

The third inclined surfaces γ1 and γ2 are provided so that the first inclined surfaces α1 and α2 and the second inclined surfaces β1 and β2 can easily come into contact with each other. In order for the first inclined surfaces α1 and α2 and the second inclined surfaces β1 and β2 to come into contact with and adhere to each other, the anode seal 9 and the cathode seal 10 need to be compressed in the stacking direction. The volume of the seal compressed by the compression can be accommodated in the gap formed by the third inclined surfaces γ1 and γ2.
As a result, the first inclined surfaces α1 and α2 and the second inclined surfaces β1 and β2 can be brought into contact with and brought into close contact with each other with a smaller compressive force as compared with the case where there is no gap.
Further, as will be described below, it is provided so as to be easily deformed by compression during assembly. The third inclined surfaces γ1 and γ2 are different from the second inclined surfaces β1 and β2 and have different inclination angles. Instead of the third inclined surfaces γ1 and γ2, or together with the third inclined surfaces γ1 and γ2, a fourth inclined surface having an inclination different from the first inclined surface is provided on the outer peripheral surface of the anode diffusion layer 5 and the cathode diffusion layer 6. May be.

In addition, in this example, the first, second, and third inclined surfaces have a shape of a part of an outer surface of the truncated cone.

<Stacking procedure>
The stacking procedure will be described. The first is assembly on the anode side. As shown in FIG. 8, the anode insulating plate 11 is placed on an assembly table (not shown). The anode separator 7 is stacked on it (above the paper surface). An annular anode seal 9 is placed on the anode separator 7, and the anode diffusion layer 5 is stacked so that the second inclined surface β1 of the anode seal 9 and the first inclined surface α1 of the anode diffusion layer 5 are aligned with each other. After that, the electrolyte membrane 2 coated with the anode electrode layer 3 and the cathode electrode layer 4 is stacked. The subsequent steps are the cathode side assembly. After first stacking the cathode diffusion layer 6 on the electrolyte membrane 2, the first inclined surface α2 of the cathode diffusion layer 6 and the inner side surface of the annular cathode seal 10 should be aligned with the second inclined surface β2. Stack the cathode seals 10. Further, the cathode separator 8 and the cathode insulating plate 12 are stacked in this order.

<Compression work>
Next, an assembling table (not shown) on which the anode insulating plate 11 is placed is installed in a press (not shown), and the cathode insulating plate 12 is pressed downward toward the assembling table to compress the compression force. Add. FIG. 8 shows a state in which no compressive force is applied, so that the thickness of the anode seal 9 is thicker than the anode diffusion layer 5 by δ1. Similarly, the cathode seal 10 is thicker than the cathode diffusion layer 6 by δ2.

When a compressive force is applied from this state, the thickness of the anode seal 9 is elastically deformed and thinned, and the volume of the anode seal 9 corresponding to this deformation is directed toward the outside of the outer end surface of the anode seal 9 ( (Indicated by arrow f1) or in a direction (indicated by arrow g1) toward the third inclined surface γ1 on the lower side of the anode seal 9 in the drawing. At this time, the first inclined surface α1 of the anode diffusion layer 5 is gradually and strongly pressed against the second inclined surface β1 of the annular anode seal 9 on the upper side of the drawing. Since the anode seal 9 is elastically deformed by the compressive force as described above, the gap 43 formed by the electrolyte membrane 2, the anode electrode layer 3, and the inner end surface β1 of the anode seal 9 can be eliminated.

Similarly, the thickness of the cathode seal 10 is also elastically deformed and thinned by the compressive force, and the capacity corresponding to this deformation is directed toward the outside of the outer end surface of the cathode seal 10 on the upper side of the paper (indicated by arrow f2) and the cathode The seal 10 is deformed in a direction (indicated by an arrow g2) toward the third inclined surface γ2 on the upper side of the paper surface. By such elastic deformation of the cathode seal 10, the gap 44 formed by the cathode diffusion layer 6, the cathode seal 10 and the cathode separator 8 can be eliminated.

As described above, since the anode-side skimmer 20 and the cathode-side skimmer 21 do not exist in the electrochemical hydrogen pump of the present embodiment, the electrolyte membrane 2 is not exposed to gas. Therefore, performance degradation due to hydrogen concentration diffusion from the high pressure side to the low pressure side is suppressed.

<Evaluation device>
FIG. 9 is a schematic cross-sectional view of the evaluation device 40 for the electrochemical hydrogen pump 23. A current is applied to the electrochemical hydrogen pump 23 by the voltage application unit 19, and low-pressure hydrogen is supplied to the electrochemical hydrogen pump 23 by the hydrogen cylinder 24 and the regulator 25. This low-pressure hydrogen is humidified by a bubbler 26 and a heater 27. Excess hydrogen not used in the electrochemical hydrogen pump 23 is lowered in dew point by the gas-liquid separator 28 and the cooling device 29. On the high pressure side, the pressure is measured by the pressure gauge 30, and the exhaust valve 31 on the downstream side is normally closed, and is opened when the pressure exceeds a certain value.

However, the opening degree of the exhaust valve 31 is adjusted so that sufficient pressure loss occurs. That is, the opening of the exhaust valve 31 is adjusted so that the pressure of hydrogen after passing through the exhaust valve 31 is reduced to almost atmospheric pressure (about 1.1 times the atmospheric pressure) due to the pressure loss generated in the exhaust valve 31. Is set.

The hydrogen depressurized to about atmospheric pressure has its dew point lowered by the gas-liquid separation device 32 and the cooling device 33, is diluted inside the diluting device 35 by the nitrogen supplied from the nitrogen cylinder 34, and is then exhausted to the outside. It flows into the mouth 36.

In the subsequent processes, the heater 27 was set to 65 (°C) and the cooling devices 29 and 33 were set to (20°C).

<Evaluation process>
A process for evaluating the hydrogen pump of the present application will be described.
As shown in FIG. 9, the electrochemical hydrogen pump 23 according to the first embodiment is connected.
-The three-way valve 37 is switched from the atmosphere open position (arrow A) to the closed side (arrow B).
-Operate the valve 38 of the nitrogen cylinder for dilution. The diluter 35 is flushed with nitrogen.
The valve 39 of the hydrogen cylinder 24 and the regulator 25 are operated to supply 1.1 (MPa) of hydrogen to the electrochemical hydrogen pump 23.
-The voltage application unit 19 is turned on, and the current value is set so as to be 1.0 (A/cm2) calculated from the electrode area.
・Continue to energize for 5 minutes. Record the pressure gauge 30 value after 5 minutes.
-The voltage application unit 19 is turned off, the supply of hydrogen is stopped by operating each valve, and then the supply of nitrogen for dilution is stopped.
Finally, the three-way valve 37 is switched from the closed position (arrow B) to the atmosphere open side (arrow A).
-Repeat the operations (1) to (8) 50 times.
(10) The electrochemical hydrogen pump 23 according to the first embodiment of the present application is removed.

<Evaluation result>
A polygonal line a in FIG. 10 is a diagram in which the number of times of the above process is plotted on the horizontal axis and the pressure ratio at each number of times of the electrochemical hydrogen pump 22 in Patent Document 2 is plotted on the vertical axis.

The polygonal line b is a diagram in which the number of times of the above process is plotted on the horizontal axis and the pressure ratio at each number of times of the electrochemical hydrogen pump 23 in the first embodiment of the present application is plotted on the vertical axis.

The polygonal line b has a pressure ratio of 0.98 to 0.99 almost every time from the first time to the 50th time, although there is some variation. On the other hand, in the polygonal line a, the pressure ratio is lower by about 0.01 point from the first time than in the polygonal line b, and sharply decreases in the vicinity of the 50th time.

In the polygonal line a, the reason why the pressure ratio is low from the first time is considered to be that hydrogen concentration diffusion occurs from the cathode side skimmer 21 of the electrochemical hydrogen pump in FIG. 4 to the anode side skimmer 20.

Further, in the polygonal line a, the cause of the rapid decrease near the 50th time is that the hydrogen that has permeated the electrolyte membrane 2 and the oxygen in the air remaining in the cathode channel 8b of the cathode side separator at the beginning of each current application. It is conceivable that a combustion reaction occurred in the vicinity of the cathode-side skimmer 21 and the electrolyte membrane 2 was gradually damaged.

On the other hand, in the polygonal line b in the first embodiment of the present application, the pressure ratio is almost stable from the first time to the 50th time, and the compression efficiency does not decrease.

Therefore, there is no place where the electrolyte membrane 2 is exposed to gas unlike the cathode-side skimmer 21 (FIG. 1) and the anode-side skimmer 20 (FIG. 1). As a result, it is considered that reverse diffusion of hydrogen and damage to the electrolyte membrane 2 are less likely to occur.

The polygonal lines c and d are the data of the second embodiment below, which will be described later.
(Embodiment 2)
FIG. 11 is a schematic cross-sectional view of the electrochemical hydrogen pump 41 in the second embodiment.
<Overall structure>
The electrochemical hydrogen pump 41 according to the second embodiment is different from the electrochemical hydrogen pump 23 according to the first embodiment in that the anode separator 7 and the cathode separator 8 have the first protrusions 45. Items not described are the same as those in the first embodiment.

That is, the anode separator 7 and the cathode separator 8 are each provided with the first protrusion 45, and the first protrusion 45 locally presses the anode seal 9 and the cathode seal 10 during assembly. is there.

As a result, the outer surface α1 of the anode diffusion layer 5 and the inner surface β1 of the anode seal 9 and the outer surface α2 of the cathode diffusion layer 6 and the inner surface β2 of the cathode seal 10 can be strongly adhered.

<Evaluation>
A polygonal line c in FIG. 10 is plotted with the horizontal axis representing the number of times of the above-mentioned process, and the vertical axis representing the pressure ratio of the electrochemical hydrogen pump 41 in the second embodiment of the present application obtained according to the same process as in the first embodiment. It is a diagram.

According to the polygonal line c in FIG. 10, the electrochemical hydrogen pump 41 according to the second embodiment of the present application has a pressure ratio of 0.98 to 0.99 almost every time from the first time to the 50th time, although there are some fluctuations. No reduction in efficiency has occurred.

Therefore, unlike the cathode-side skimmer 21 and the anode-side skimmer 20 of the electrochemical hydrogen pump 22 in Patent Document 2, there is no place where the electrolyte membrane 2 is exposed to gas, so that back diffusion of hydrogen and damage to the electrolyte membrane are less likely to occur. It is thought that it has become.
(Embodiment 3)
FIG. 12 is a schematic cross-sectional view of the electrochemical hydrogen pump 42 according to the third embodiment before being fastened.

<Overall structure>
The electrochemical hydrogen pump 42 in the third embodiment is different from the electrochemical hydrogen pump 41 in the first embodiment in that the anode seal 9 and the cathode seal 10 have the second protrusions 46. Items not described are the same as those in the first embodiment.

That is, the anode seal 9 and the cathode seal 10 are provided with the second protrusion 46, and the second protrusion 46 is locally pressed against the anode separator 7 and the cathode separator 8 during assembly. As a result, the outer surface of the anode diffusion layer 5 and the inner surface of the anode seal 9 and the outer surface of the cathode diffusion layer 6 and the inner surface of the cathode seal 10 can be strongly adhered.

<Evaluation>
The polygonal line e in FIG. 10 is plotted with the horizontal axis representing the number of times of the above process, and the vertical axis representing the pressure ratio of the electrochemical hydrogen pump 42 in the third embodiment of the present application obtained according to the same process as in the first embodiment. It is a diagram.

According to the polygonal line e in FIG. 10, the electrochemical hydrogen pump 42 according to the third embodiment of the present application has a pressure ratio of 0.98 to 0.99 almost every time from the first time to the 50th time, although there is some variation, but the compression ratio is 0.98 to 0.99. No reduction in efficiency has occurred.

Therefore, unlike the cathode-side skimmer 21 and the anode-side skimmer 20 of the electrochemical hydrogen pump 22 in Patent Document 2, there is no place where the electrolyte membrane 2 is exposed to gas, so that back diffusion of hydrogen and damage to the electrolyte membrane are less likely to occur. It is thought that it has become.

(effect)
In the electrochemical hydrogen pump of the present invention, the anode seal is pressed against the anode diffusion layer, and the cathode seal is pressed against the cathode diffusion layer, with the inclined surfaces pressed against each other. As a result, the anode diffusion layer and the anode seal can be brought into close contact with each other and the cathode diffusion layer and the cathode seal can be prevented from leaving a gap. As a result, there is no gap between the diffusion layer and the seal, and the electrolyte membrane is not exposed to gas, so the performance degradation due to the hydrogen concentration diffusion from the high pressure side to the low pressure side is suppressed, so It is the most suitable as a hydrogen compression device for a small hydrogen filling device.

Further, since it is not necessary to expand the low-voltage side anode diffusion layer 5 to a region that does not contribute to the reaction, the cost of the anode diffusion layer 5 made of an expensive Ti metal sintered body can be suppressed.
(Embodiment 4)
FIG. 13 is a schematic cross-sectional view of the electrochemical hydrogen pump 50 according to the fourth embodiment. FIG. 6 is a diagram corresponding to FIG. 5 of the first embodiment. Items not described are the same as those in the first embodiment.

The electrochemical hydrogen pump 50 in the fourth embodiment is different from the electrochemical hydrogen pump 23 in the first embodiment in the structure of the connecting portion between the cathode seal 10 and the cathode diffusion layer 6. Similarly, the structure on the anode side is also the same.

The fourth inclined surface Z2 is provided on the cathode diffusion layer 6, that is, on the cathode separator 8 side.
The inclination of the fourth inclined surface Z2 is perpendicular to the plane of the surface of the electrolyte membrane 2 (electrode layer). That is, the inclination of the fourth inclined surface Z2 is more perpendicular to the plane of the surface of the electrolyte membrane 2 (electrode layer) than the second inclined surface α2.

The contact area between the cathode diffusion layer 6 and the cathode separator 8 in which the fourth inclined surface Ζ2 is formed in addition to the first inclined surface α2 is the cathode in which the fourth inclined surface Ζ2 is not formed and only the first inclined surface α2 is formed. It is larger than the contact area between the diffusion layer 6 and the cathode separator 8. Therefore, the contact resistance between the two is small, so that the IR loss can be reduced and the power efficiency can be improved. The same applies to the anode side. Electric power can be made more efficient to obtain high-pressure hydrogen.

The inclination of the fourth inclined surface Z2 is maximum perpendicular to the plane of the surface of the electrolyte membrane 2 (electrode layer). Above the vertical, it is difficult to assemble the electrochemical hydrogen pump 50.

(Throughout)
The first to fourth embodiments can be combined. For example, the cathode side structure of the first embodiment and the anode side structure of the second embodiment can be combined.

Further, in the above embodiment, the invention is applied to both the cathode side and the anode side, but it may be applied to only the cathode side or the anode side.

It can be used as a hydrogen compression device for the hydrogen filling device of the present invention.

DESCRIPTION OF SYMBOLS 1 power generation stack 2 electrolyte membrane 3 anode electrode layer 4 cathode electrode layer 5 anode diffusion layer 6 cathode diffusion layer 7 anode separator 7a anode flow path 8 cathode separator 8b cathode flow path 9 anode seal 10 cathode seal 11 anode insulating plate 12 cathode insulating plate 13 bolt 14 nut 15 anode inlet 16 anode outlet 17 cathode inlet 18 cathode outlet 19 voltage application unit 20 anode side skimmer 21 cathode side skimmer 22 electrochemical hydrogen pump 23 electrochemical hydrogen pump 24 hydrogen cylinder 25 regulator 26 bubbler 27 heater 28 gas-liquid Separator 29 Cooling device 30 Pressure gauge 31 Exhaust valve 32 Gas-liquid separating device 33 Cooling device 34 Nitrogen cylinder 35 Diluting device 36 Exhaust port 37 3-way valve 38 Valve 39 Valve 40 Evaluation device 41 Electrochemical hydrogen pump 42 Electrochemical hydrogen pump 45 First protrusion 46 Second protrusion 43, 44 Skimmer 50 Electrochemical hydrogen pump φd Diameter φD Diameter δ Width α1 First inclined surface α2 First inclined surface β1 Second inclined surface β2 Second inclined surface γ1 Third inclined surface γ2 Third Inclined surface Z1 4th inclined surface Z2 4th inclined surface δ1 size δ2 size

Claims (7)

The one surface of the anode electrode and the anode diffusion layer position, and the electrolyte membrane and the cathode electrode and the Ca cathode diffusion layer positioned on the other side, an anode seal having an opening surrounding the anode diffusion layer,
A cathode seal having an opening surrounding the cathode diffusion layer,
An anode separator located outside the anode seal,
A cathode separator located outside the cathode seal,
The outer surface of the anode diffusion layer or the cathode diffusion layer is a first inclined surface, and the inner curved surface of the opening of the anode seal or the cathode seal is a second inclined surface,
A mating surface is formed by the first inclined surface and the second inclined surface, and the mating surface is an electrochemical hydrogen pump inclined with respect to the cathode electrode or the anode electrode,
The electrochemical hydrogen pump, wherein an inner curved surface of the anode seal or the cathode seal has a third inclined surface which is an inclined surface different from the second inclined surface. The one surface of the anode electrode and the anode diffusion layer position, and the electrolyte membrane and the cathode electrode and the Ca cathode diffusion layer positioned on the other side, an anode seal having an opening surrounding the anode diffusion layer,
A cathode seal having an opening surrounding the cathode diffusion layer,
An anode separator located outside the anode seal,
A cathode separator located outside the cathode seal,
The outer surface of the anode diffusion layer or the cathode diffusion layer is a first inclined surface, and the inner curved surface of the opening of the anode seal or the cathode seal is a second inclined surface,
A mating surface is formed by the first inclined surface and the second inclined surface, and the mating surface is an electrochemical hydrogen pump inclined with respect to the cathode electrode or the anode electrode,
The outer surface of the anode diffusion layer or the cathode diffusion layer is
An electrochemical hydrogen pump having a fourth inclined surface which is an inclined surface different from the first inclined surface. The one surface of the anode electrode and the anode diffusion layer position, and the electrolyte membrane and the cathode electrode and the Ca cathode diffusion layer positioned on the other side, an anode seal having an opening surrounding the anode diffusion layer,
A cathode seal having an opening surrounding the cathode diffusion layer,
An anode separator located outside the anode seal,
A cathode separator located outside the cathode seal,
The anode diffusion layer, or the outer surface of the cathode diffusion layer is a first inclined surface, the anode seal, or the inner curved surface of the opening of the cathode seal is a second inclined surface,
A mating surface is formed by the first inclined surface and the second inclined surface, and the mating surface is an electrochemical hydrogen pump inclined with respect to the cathode electrode or the anode electrode,
An electrochemical hydrogen pump in which the anode seal or the cathode seal is thicker than the anode diffusion layer or the cathode diffusion layer. The anode diffusion layer or the cathode diffusion layer has a flat plate shape, of the upper and lower surfaces, the wider surface is arranged toward the electrolyte membrane side,
The anode seal or the cathode seal has a flat plate shape, and is arranged such that, of the upper and lower surfaces, the surface having the larger opening faces the electrolyte membrane side. Electrochemical hydrogen pump. The electrochemical hydrogen pump according to any one of claims 1 to 4, wherein there is no gap between the anode diffusion layer and the anode seal or a gap between the cathode diffusion layer and the cathode seal. The anode separator or the cathode separator is provided with a first protrusion,
The electrochemical hydrogen pump according to any one of claims 1 to 5, wherein the first protrusion has a structure for pressing the anode seal or the cathode seal. 7. The cathode seal or the anode seal is provided with a second protrusion, and the second protrusion is configured to press the anode separator or the cathode separator. The electrochemical hydrogen pump according to item 1.

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